Fuel pump



Jan. 21, 1941. EYEN BER 2,229,231

FUEL PUMP Filed Feb. 25, 1939 INVENTOR.

HENEV WE YEA/55,96

% as BY ATTORNEY.

Patented Jan. 21, 1941 UNITED STATES 2,229,231 FUEL PUMP Henry Weyenberg, Holland, Mich assign: to Holland Furnace Company, Holland, Mich, a corporation of Michigan 'Application February 25, 1939, Serial No. 258,408

7 Claims.

This invention relates to fuel pumps for supplying liquid fuel to oil burners, and more particularly to devices for bleeding air from the pump housing.

The presence of air in a fuel pump disturbs the operation thereof and reduces its efficiency. For that reason prior fuel pumps usually have been supplied with a port in a wall of the high pressure section through which the air may be removed. Such a' port is closed by a removable.

It is the primary object of this invention to eliminate the above objections by providing a port within the interior of the housing to allow the air which may become trapped within the high pres- 25 sure chamber of the pump to escape through the return line to the source of fuel supply. Another object of the invention is to provide a means for bleeding air from the pump which will be simple and economical to manufacture, and which will 30 be positive in its operation.

These and other objects ancillary thereto will become more apparent in the following specification when read in the light of the accompanying drawing which forms a part thereof. In the 5 drawing:

Figure 1 is a plan view of a pump embodying this invention; a

Fi u e 2 is a cross-sectional view taken on substantially the line 2-2 of Figure l; and

40 Figure 3 is a fragmentary cross sectional view similar to Figure 1 but showing a modified form of port for bleeding air from the high pressure chamber of the pump.

The pump shown in Figures 1 and 2 comprises a housing It which is divided into four chambers by partitions Illa, H and I2. These four chambers are the inlet chamber IS, the filter chamber IS, the high pressure chamber I6 and the relief chamber IT. The inlet chamber 18 and the filter 50 chamber l5 together comprise what may be termed the low pressure chamber of the pump.

The partition Illa has an opening extending through it and seated in the opening 20 is the upper end of a porous filter screen I 9. The latter 5 extends downwardly into the filter chamber l5 with the pump casing.

and is so arranged that all fuel entering the filter chamber from the inlet chamber l8 must pass through the screen. The screen is held in the opening by means of a spring 2|, one end of i which is seated in a cup-shaped plug 22 threaded 5 into a hole in the housing I.

a The major part of the partition II is enlarged at I: in order to receive a pump casing ll, the latter being pressed into a bore in said enlargement. Within the pump casing isa pump cham- 10 ber 32. An inlet duct 28 extending through the partition II and pump casing It connects the 1 pump chamber 32 with the filter chamber IS, in order that fuel may enter the pump chamber from the filter chamber. 16

v The pump. chamber houses the two moving parts of a rotary pump. These two moving parts are the gear 2| which issecured to the pump drive shaft 25, and the notched ring- 26. The gear 24 and ring 26 are located ,eccentrically with re- 20 spect to each other and are separated at one side by a partition lug 21 which is preferably integral Rotary pumps of this type are well known in the art andit is believed to be unnecessary to describe the pump in detail. 25

' The high pressure chamber l6 has an inlet duct 29 connecting it with the pump chamber 32 and three outlets, a main outlet 30, a relief outlet 3|, and an air bleeding outlet consisting of two con necting ports and 49. The main outletlll.is--' formed in a plug 33 which is threaded into the housing l0; The mouth of the outlet 30 is tapered to form a valve seat 14. A

The relief outlet II is formed in a sleeve 36 threaded into an opening in the partition I! di- 35 rectly above the mainoutlet 30. The sleeve 36 extends upwardly into the relief chamber and has ports 38 in its sides just above the partition l2. v

A valve plunger 31 is slidably received in the 40 sleeve 36, the upper'part of which forms a guide for the plunger. The lower portion of the plunger 36 is reduced in diameter, thereby forming a shoulder Ill. The lower end 39 of the plunger, though larger than the. portion immediately above it, is also smaller than the sleeve in order to allow fuel to flow past said end under certain conditions. The lower end of the plunger carries a conical valve 35 which seats in the valve seat 34 when the pump is inoperative or thereis air in the high pressure chamber I.

The plunger 31 is biased downwardly by a helical spring ll located between washers 42 and the upper end of the plunger 31. The washers are secured to a screw 43 threaded into a support 44 which in turn is threaded into the top of the housing. The support is covered by a threaded cap 45 provided with a threaded plug 45. The latter is readily removable to afford access to the screw 43. By adjusting the screw 43 the tension of spring 4| may be easily regulated.

The air bleeding outlet is composed of two small ports 48 and 49'which enter a horizontally extending bore 50 tapered at its inner end. This bore is threaded for the reception of an Allen head set screw 5|, having a tapered point fitting the end of the bore 50. The bore 50 extends longitudinally of the partition l2 and communicates with the exterior of the housing, whereby the set screw 5| may be entirely removed, if desired, to afford direct communication between the high pressure chamber l5 and the atmosphere.

The pump housing is adapted to be connected to the supply tank and oil burner by means of suitable pipes and pipe fittings. In order for it to be so connected the housing is provided with nipples 23, 33a and 53, threaded into openings therein. The nipple 23 connects the supply line to the inlet chamber, nipple 33a connects the outlet 30 to the oil burner line, and nipple 53 connects the relief chamber through an open-e ing 52 to the supply tank. The latter. nipple allows air and excess fuel to escape from the housing back to the tank.

The operation of the device is as follows:

When the pump proper is not being rotated,

or when the pump is rotating but there is air in either the pump chamber or the high pressure chamber, the outlet. valve 35 will be held against its seat 34 by means of the spring 4| because the pressure in thehigh pressure chamber will not be great enough to raise this valve from its seat. In order to rid the high pressure chamber of air the pump is started and the set screw 5| is backed out of the bore sufilciently to uncover the two ports 48 and 49. The air trapped in the high pressure chamber will then flow out through these ports into the relief chamber l1 and thence through the outlet 52, nipple 53 and the return line to the supply tank. As soon as the high pressure chamber IB' is rid of air the set screw 5| is threaded home in its seat, closing the ports 48 and 49.

When the ports 48 and 49 are closed the pump will soon build up the pressure in the chamber IS. The pressure will act on the lower end of the plunger 3'! and shoulder 40, raising it, and the needle valve 35 with it, thereby opening the outlet port 30. Fuel may then flow to the oil burner.

If the pressure in chamber l5 becomes greater than that required during the normal operation of the burner, the plunger 31 will be lifted still further, thereby uncovering the ports 38. Excess fuel will then escape through these ports to the relief chamber I! from which it may flow back to the supply tank through the outlet 52.

It will be seen from the foregoing that this invention provides a simple and positive means for venting the high pressure chamber when desired, and thus ridding it of air. It will also be apparent that it is unnecessary to entirely remove any plug from the pump housing in order to bleed air from the interior thereof, and therefore, there is no possibility of fuel escaping from the pump housing.

The pump just described is constructed so that it may be used 111;.8: system in which it is impossible or undesirable to employ a return line for returning excess fuel to the supply tank. In

order that the pump may be employed in such a system it is provided with an opening 54 in partition Just above the pump inlet duct 28. This opening is normally closed by a threaded plug 55. A removable plug 55 is threaded into the housing III above the plug 55 in order to afford access to the latter.

when used in a so-called one line system, that is, without a return line, the opening 52 is closed by a suitable plug and plug 55 is entirely removed. The set screw 5| is entirely removed and the pump is run until oil appears in the bore 50. This indicates that all air is purged from the pump housing. The set screw is reinserted and threaded home. The pump then acts in the manner previously described, except that fuel which escapes through the relief outlet 3| into the relief chamber l1 flows through the opening 54 to the low pressure side of the pump instead of through opening 52 back to the supply tank.

Figure 3 shows a modified form of the invention. In general the pump is identical with that previously described, but instead of having a manually controlled air bleeder outlet it is provided with an automatic valve, whereby whenever air appears in the high pressure chamber it is automatically released into the relief chamber.

In thisdevice the wall |2a of the high pressure chamber |5a is provided with a bore 60. In-

serted in the bore are two valve seats GI and 52,

each having a small opening therethrough. The valve seats 5| and 52 are spaced apart to accommodate a. ball check valve 53 which rests on the lower seat 5| due to its own weight as long as there is. no fluid pressure in the chamber lia. When the pump is operated the ball 63 will be lifted slightly to allow air to leak past the ball.

As soon as the high pressure chamber |5a is full of oil, however, the pressure in the chamber l5 will rise, and ball 58 will be lifted from its seat GI and held against seat 52, thereby closing the air bleeding outlet. Any further increase in oil pressure will be compensated for by escape of oil through the relief outlet Ila, as in the previously described device.

The scope of the invention is indicated in the appended claims.

I claim:

1. A liquid fuel pump comprising a casing, a low pressure chamber in said casing having an inlet opening for the supply of liquid fuel thereto, a high pressure chamber in said casing having an outlet opening for the discharge of liquid fuel therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted to be opened by the pressure of the fuel wi thin the high pressure chamber, a relief chamber in said casing having therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted to be opened by the pressure of the fuel within the high pressure chamber, a relief chamber in said casing having an outlet opening for the discharge of air and fuel therefrom, means for purging the high pressure chamber of air comprising a passageway between the high pressure chamber and the relief chamber, and means operable from the exterior of the casing for opening and closing said passageway.

3. A liquid fuel pump comprising a casing, a low pressure chamber in said casing having an inlet opening for the supply of liquid fuel thereto, a high pressure chamber in said casing having an outlet opening for the discharge of liquid fuel therefrom, a pump positioned between the two chambers for transmitting fuel from the. low pressurechamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted to be opened by the pressure of the fuel in the high pressure chamber, a relief chamber in said casing having an outlet opening for the discharge of air and fuel therefrom, said relief chamber and high pressure chamber having a common wall extend- Ling laterally from a side wall of said casing,

means for purging the high pressure chamber of air comprising a passageway extending through said common wall between the high pressure chamber and the relief chamber, and manually operable means for closing said passageway.

4. A liquid fuel pump' comprising a casing, a low pressure chamber .in said casing having an inlet opening for the supply of liquid fuel thereto, a high pressure chamber in said casing having an outlet opening for the discharge of liquidfuel therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted'to be opened by the pressure of the fuel in the high pressure chamber, a relief chamber in said casing having an outlet opening for the discharge of air and fuel therefrom, said relief chamber and high pressure chamber having a common wall extending laterally from a side wall of said casing, means for purging the high pressure chamber of air comprising a passageway extending through said common wall between the high pressure chamber and the relief chamber, a bore extending through said side wall into said common wall and intersecting said passageway, the axis of said bore lying in the plane of said common wall, and means movable axially of said bore for opening and closing said passageway.

5. A liquid fuel pump comprising a casing, a low pressure chamber in said casing having an inlet opening for the supply of liquid fuel thereto, a high pressure chamber in said casing having I I an outlet opening for the discharge of liquid fuel therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber,

extending through said side wall into said common wall and intersecting said passageway, the axis of said bore lying in the plane of said common wall, and a threaded valve in said bore movable axially thereof for opening and closing said passageway.

6. A liquid fuel pump comprising a casing, a low pressure chamber having an inlet opening for the supply of liquid fuel thereto, a high pressure chamber having an outlet opening for the discharge of liquid fuel therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted to be'opened by the pressure ofthe fuel within the high pressure chamber, a relief chamber having an outlet opening for the discharge .of air and fuel therefrom, means for purging the high pressure chamber of air comprising a passageway between the high pressure chamber and the relief chamber, and a valve associated with said passageway adapted to close said passageway only when the high pressure chamber is completely filled with fuel.

'7. A liquid fuel pump comprising a casing, a low pressure chamber having an inlet opening for the supply of liquid fuel thereto, a high pres-' sure chamber having an outlet opening for the discharge of liquid fuel therefrom, a pump positioned between the two chambers for transmitting fuel from the low pressure chamber to the high pressure chamber, a valve associated with the outlet opening in the high pressure chamber adapted to be opened by the pressure of the fuel within the high pressure chamber, a relief chamber having an outlet opening for the discharge of air and fuel therefrom, means for purging the high-pressure chamber of air comprising a passageway between the high pressure chamber and the relief chamber, and an automatically operated check valve associated with said passageway adapted to close said passageway only when the high pressure chamber is completely filled with fuel.

'HENRY WEYENBERG. 

